The present invention refers to a device for fixing a tube member in a cavity of a patient.
By such tube members, it is in the present application referred to all types of pipes, which are intended to be introduced into a patient, i.e. a human being or an animal. It may for instance be so-called endotracheal tubes, which are intended to be introduced into the trachea, corresponding tubes for the introduction into the gullet, different types of hoses, cannulae, catheters etc. for various cavities of the patient.
Frequently, it is desirable to fix such hoses or tube members in the cavities of the body of the patient in order to enable introduction and/or discharge of different fluids, i.e. liquids or gases. In that connection, the hose is to seal against an organic surface, which in its structure may be irregular as well as resilient. In order to obtain such a tight fixing, various types of fixing members are used. There are large requirements on such fixing members, in particular if the tube member also is subjected to an axial movement, bending movement, turning movement, rotation and/or if the diameter of the cavity is varying over the time, for instance by pulsation.
The organic contact surface of the cavity, against which the fixing member is to seal, consists of living material, which means that the blood supply to the surrounding tissue must not be hindered. Such an obstruction, which may appear if the contact pressure of the fixing member is too large, may rapidly result in serious consequences through the focal death of tissue.
It is known today to use inflatable balloons as fixing members, which in the inflated state are to be pressed against the wall of the cavity, and in such a way fix the tube member in the cavity and at the same time to provide a proper sealing. The inflatable balloons used today are connected with problems with regard to leakage as well as tissue injuries.
Such leakage may be very serious, for instance in connection with a respirator treatment with the use of the endotracheal tube mentioned above. If leakage arises, contaminated secretion from the upper airways may leak bypassing the balloon down to the sterile lungs and cause pneumonia. During such treatment, pressure injuries on the tissue of the mucous membrane are also frequently present when using such balloons.
The rubber/plastic materials, which have thin walls and which are used in the casings of the fixing members are permeable. Consequently, it is difficult to maintain a consistent working pressure in the balloon. Gas is diffusing outwardly, which decreases the pressure and increases the risk of leakage. The relation is opposite when using certain anaesthetic gases, which contain nitrogen oxide, wherein the gas is flowing in an opposite direction and the working pressure within the balloon increases successively with a following risk of pressure injuries on the tissue.
Such a conventional balloon, seen in a longitudinal sectional view, has a shape, which is circular, oblong or oval. It means that a changed working pressure within the balloon gives a corresponding change of the external contact pressure applied to the wall of the cavity.
Furthermore, these known balloons have in a freely inflated state a smallest given extent. If the inner extent of the cavity to be sealed by the balloon is less, small axial folds are formed on the contact surface of the balloon. Such folds lead to leakage and may also be irritating to the tissue. Also in case of a moderate turning movement of the balloon in relation to the wall of the cavity, fold formation can appear.